DZone Snippets: language code

Ruby word count

sikelianos (Zeke Sikelianos) — Wed, 06 Feb 2008 19:29:34 GMT



module StringExtensions

  def words

    s = self.dup

    s.gsub!(/\w+/, 'X')

    s.gsub!(/\W+/, '')

    s.length

  end

end

Fast stop word detection in Ruby

peter (Peter Cooperx) — Mon, 02 Jul 2007 03:10:16 GMT

Requires BloominSimple (a pure Ruby Bloom filter class).

List of stop words obtained from http://www.dcs.gla.ac.uk/idom/ir_resources/linguistic_utils/stop_words

# Detect stop words QUICKLY

# Uses a bloom filter instead of searching literally through a list of stopwords

# for > 3x speed increase

# 

#    using bloom filter: 2.580000   0.030000   2.610000 (  2.698829)

#  using literal search: 7.850000   0.120000   7.970000 (  8.181684)





require 'bloominsimple'

require 'digest/sha1'

require 'pp'



# Create a simple bloom filter that uses a SHA1 hash (more effective than BloominSimple's default hashing)

b = BloominSimple.new(50000) do |word|

  Digest::SHA1.digest(word.downcase.strip).unpack("VVV")

end



# Add stopwords to the bloom filter!

stopwords = []

File.open('stopwords').each { |a| b.add(a); stopwords << a.downcase.strip }



# Read in a whole dictionary of regular words

words = File.open('/usr/share/dict/words').read.split.collect{|a| a.downcase.strip }



# Define two ways to detect stopwords for comparison..

using_filter = lambda { |word| b.includes?(word) }

using_array = lambda { |word| stopwords.include?(word.downcase.strip) }

techniques = [using_filter, using_array]



# Run stopword comparisons with both techniques

t = techniques.collect { |l| words.collect { |a| l[a] } }



# See how effective the bloom filter has been compared to the literal search

if t[0] == t[1]

  puts "GOOD"

else

  words.zip(t[0],t[1]).each do |x|

    puts x.first if x[1] != x[2]

  end

end



# Now do speed benchmarks..

techniques.each { |l| puts Benchmark.measure { words.each { |a| l[a] } } }

genetic algorithm in J

cratylus (crat) — Sun, 15 Oct 2006 17:33:01 GMT



-------------  Beginning of class  pga.ijs   -------------------

coclass'pga'

create=:3 : 0

genes=: ? 4 $ 100  NB. 4 random integers 0-99

)

getgenes =: 3 : 'genes'

setgenes =: 3 : 'genes=:y.'

matewith=: 3 : 0

other=. y.

mine=. ((#genes) % 2) ? (#genes) NB. crossover

childgene=. getgenes__other '' NB. copy others intially

child=. conew 'pga'

setgenes__child ((mine { genes) (mine }) childgene)

child

)

perform =: 3 : 0 NB. dummy problem

+/ genes

)

destroy=:codestroy

-------------  End of of class  pga.ijs   ----------------------

-------------  beginning of script ga.ijs ----------------------

NB. genetic algorithm 

NB. needs pga class

NB. define a dummy target to measure fitness against

targetvalue =:  500  

fitness=: 3 : 0

object=. y.

1000 * %(targetvalue - perform__object '')

)



load jpath '~user\classes\pga.ijs'





top =: 4 : '(i.y.) { \: (fitness each x.)'  NB. pop top 10 returns the 10 fittest



pair=: 3 : 0  NB. pick two random ga objects, mate them, and return the child

pop=. y.

mom=. > (?#pop) { pop NB. must unbox!

dad=. > (?#pop) { pop NB.  # is length of boxed list

matewith__mom dad

)



NB.  pop evolve generations returns the fittest ga after 

NB. sifting the top 25 ga's

evolve=: 4 : 0

pop=. x.

n=. y.

for_k. i.n do.

kpop=.  3 : 'pop' NB. not sure if necessary to do here

newgen=.  (pair@kpop) each i.100  NB. create 100 children

best=.  (newgen top 25) { newgen NB. find the indices of the best, then select the corresponding objects

pop=. best,best,best,best  NB. not really necessary?

end.

>0{best  NB. return best

)

NB. usage  

load jpath '~user\ga.ijs'

average =: +/%#

pop=: conew&'pga' each i.100   NB. create 100 boxed ga objects

fitness each pop  NB. should show a boxed list of fitness values

average ; fitness each pop  NB. shows average fitness



fred=: pop evolve 100

fitness fred

uberfred=: pop evolve 1000



NB. the fitness values increase pretty slowly which is disappointing

NB. probably needs some mutation :)

-------------    end of script ga.ijs     ----------------------

ruby language features

pannous () — Thu, 29 Jun 2006 01:27:48 GMT

Unsorted list of features, howto's, suggar and evils of ruby (on rails)



# THIS FILE CONTAINS INTERESTING SNIPPETS OF RUBY/RAILS

# in order to accelerate learning and find forgotten things

#  

#  Key shortcuts!

#  ctrl+shift+v  controller/view!

#  ctrl+k  find next word

#  ctrl+m maximize editor

#  

# 

# 

#   

BAD

-----------------------

model files do not contain the classes field information 

instead this is stored in different 'migration' files

create_table "periods" do |t|

    t.column "target_id", :integer

    t.column "target_type", :string

    t.column "start_at", :datetime

    t.column "end_at", :datetime

    t.column "wholeday", :boolean

    t.column "wholeweek", :boolean

    t.column "allweeks", :boolean

  end

 NO inbuild multi dimensional arrays

DANGER!!!!!

and is not && !!!!!!!!!!!!!!!!!!!!!!!!

return x==7 and y==8  => void value expression!!!

return x==7 && y==8  !!!

nr==0 (evaluates string.nil? !!!!!!!  "0"==0 -> false!!!!)

nr.to_i==0 !!



#ANNOYANCES:

+ operator for string is really baad :

cannot convert nil into String !!! 

puts "teacher "+ @lesson.teacher

 "last saved : "+ DateTime.now.to_s  #to_s !!! neccessary!!!!!!! (and ugly)

"nr"+rand(10).to_s#!!!



Language buggy: (see http://public.transcraft.co.uk/blog/index.html)

ActionController::RoutingError (Recognition failed for "/images/btnbg.gif"):



helpers are only for views!! (ApplicationController is what you need)



@links = Link.find_by_sql [

"SELECT * from links where link like '"+ @a +"%' order by id asc"]

  #endwith startwith

s = "Hello, world"

/^Hello/.match( s ) 	>> true

/world$/.match( s ) 		>> true

  

 



  

  -------------------------------------

Good

********************



class.byname:



  alle= eval(type+".find(:all)")

  Object.const_get("Array")



# default values

def initialize(definitions=[], word = nil)       

      @definitions = definitions

      @word = word

    end





rake db_schema_dump !!! instead of writing the migration files yourself



rake --help

rake migrate VERSION=n  #runs from 0 to n !!!!!!!!!!!





Customer.find_all [ "company = ?", company ]

und wenn man eine LIKE '%xx%' Abfrage erstellen möchte:

Customer.find_all [ " company LIKE ? ", '%#{company}%' ]



string arrays:

x= %w(Montag Dienstag) is short for 

y= ["Montag" ,"Dienstag"]



<%= sortable_element('listOrTableId' , :url => { :action => 'move' }) #, :update => 'test-id',:tag => 'tr',  :complete => visual_effect(:highlight, q.id))%>



<%= observe_field(:search,

	:frequency => 0.5,

	:update => :results,

	:url => { :action => :search }, 

	:loading => "Element.show('indicator_gif_id')",

	:complete => "Element.hide('indicator_gif_id')") 

	%>





/// HOW TOs  (mixed with 'good')



global functions !

put them in application.rb (ApplicationController)









Regular expressions

#substitute patterns (m=LineBreaks u=Unicode i=IgnoreCase)

a=a.gsub(//mui, "")  # yeah right nice naming, suckers! 



send_file or send http response data

  send_data @person.picture, :filename => @person.filename, :type => "image/jpeg", :disposition => "inline"



require 'net/ftp'

 ftp = Net::FTP.new('ftp.netlab.co.jp') 

 ftp.login files = ftp.chdir('pub/lang/ruby/contrib')

  files = ftp.list('n*') 

  ftp.getbinaryfile('nif.rb-0.91.gz', 'nif.gz', 1024)

   ftp.close



#reflection : 

list.class.reflect_on_all_associations



>>>>>>>regex<<<<<<<<

// greedy !!!!

puts "a[bcb]d[bebb]rerberb]w[bsdaeb]ega".scan(/\[b(.*)b/).inspect

=>cb]d[bebb]rerberb]w[bsdae



// .*? not greedy ++

puts "a[bcb]d[bebb]rerberb]w[bsdaeb]egab".scan(/\[b(.*?)b/).inspect

=> [["c"], ["e"], ["sdae"]]



#debug over ssh:

#ruby breakpointer [options] [server uri]

#ruby script/generate scaffold x // model + view!

#http://www.rubycentral.com/book/tut_modules.html modules





  require 'net/http'

    require 'uri'

    img='http://www.macdesktops.com/?res=TRUE&category=35'

      html=Net::HTTP.get URI.parse(img)



#switch cases

 def search

    @results = Search.find(params[:query])

    case @results

      when 0 then render :action=> "no_results"

      when 1 then render :action=> "show"

      when 2..10 then render :action=> "show_many"

    end

  end

  



module Action

  VERY_BAD = 0

  BAD      = 1

  def Action.sin(badness)

    # ...

  end

end



require "trig"

require "action"

##########

MIXINS

module Debug

  def whoAmI?

    "#{self.type.name} (\##{self.id}): #{self.to_s}"

  end

end

class Phonograph

  include Debug

  # ...

end

class EightTrack

  include Debug

  # ...

end

ph = Phonograph.new("West End Blues")

et = EightTrack.new("Surrealistic Pillow")

#ph.whoAmI? 	» 	"Phonograph (#537766170): West End Blues"

#et.whoAmI? 	» 	"EightTrack (#537765860): Surrealistic Pillow"

##########################33

time=5.minutes + 30.seconds ## cool !!!!!!



5.times do |i|

   File.open("temp.rb","w") { |f|

     f.puts "module Temp\ndef Temp.var() #{i}; end\nend"

   }

   load "temp.rb"

   puts Temp.var

 end

 ################

print "Enter your name: "

name = gets

#################



Argumentlisten variabler Länge

Was aber, wenn Sie eine variable Anzahl von Argumenten übergeben wollen oder mehrere Argumente mit einem einzigen Parameter auffangen wollen? Wenn Sie einen Stern vor den Namen des Parameters nach den ``normalen'' Parametern setzen, wird genau das gemacht.

def varargs(arg1, *rest)

  "Got #{arg1} and #{rest.join(', ')}"

end





y = Trig.sin(Trig::PI/4)

wrongdoing = Action.sin(Action::VERY_BAD)

# setup:

# rails 

# ruby script\generate scaffold survey #!!  does the following too:

# ruby script\generate controller survey

# ruby script\generate model survey

#backward if

#def isanum=true

puts "It's not a number" if isanum.nil?



#$! variable!!

 rescue ScriptError, StandardError

    printf "ERR: %s\n", $! || 'exception raised'

#eval

eval(line).inspect



#regexp matching   & no brackets

if a =~ /^[-+]?\d+$/;

	puts "It's a number that may indicate positive or negative"

end



Does anyone know how to get an ID back, instead of a String?

@doctor = Doctor.find_by_name(params[:doctor][:name])

params[:parent][:doctor] = @doctor



#what is that?   yml intralanguage :(

#  database: verwurzelt_de_development

#  <<: *login





#Simplemost file IO:

IO.foreach("testfile") { |line| puts line }



arr = IO.readlines("testfile")



#Simple socket

require 'socket'

client = TCPSocket.open('localhost', 'finger')

client.send("oracle\n", 0)    # 0 means standard packet

puts client.readlines

client.close



#HTTP

require 'net/http'

h = Net::HTTP.new('www.pragmaticprogrammer.com', 80)

resp, data = h.get('/index.html', nil)

if resp.message == "OK"

  data.scan(/end #get images!



#error handling:

  f = File.open("testfile")

begin

  f.each_line {|line| puts "Got #{line.dump}" }

  # .. process

  raise ArgumentError, "Name too big", caller

rescue ArgumentError

#rescue 

  # .. handle error

else

  puts "Congratulations-- no errors!"

ensure

  f.close unless f.nil?

end

#############

 # SICK : two mechanisms!!!

 def promptAndGet(prompt)

  print prompt

  res = readline.chomp

  throw :quitRequested if res == "!"

  return res

end



catch :quitRequested do

  name = promptAndGet("Name: ")

  age  = promptAndGet("Age:  ")

  sex  = promptAndGet("Sex:  ")

  # ..

  # process information

end

#############

  

require 'breakpoint'

Thread.new do

loop do

begin

breakpoint

rescue Exception

end

end

end

Inputing non-ascii characters

korakot (Korakot Chaovavanich) — Sun, 04 Sep 2005 21:48:52 GMT

My mobile phone (6600) doesn't have a Thai input method.
(You can buy a special software to do it)
After a lot of my thought experiments, I got an easy
example from my friend on this. You do a 2-level popup menu
to let people choose from the character table.



from appuifw import *



def thai_input():

    first_list = ['  '.join(thai_char[i:i+11]) for i in range(0,77,11)]

    y = popup_menu(first_list, u'select Thai char')

    if y is not None:

        x = popup_menu(thai_char[11*y:11*(y+1)], u'select Thai char')

        if x is not None:

            t.add(thai_char[11*y + x])



thai_char = [unichr(0x0e01+i) for i in range(77)]   # 77 thai characters



app.body = t = Text()

app.menu = [(u'thai', thai_input), (u'clear screen', t.clear)] 



# wait for user to exit program

import e32      

lock = e32.Ao_lock() 

app.exit_key_handler=lock.signal

lock.wait()

For other language, you can change the unicode offset (0x0e01)
and number of characters (77) to that of your language.
One requirement for this method is that the phone must be
able to display font in your language already.
(I have previously install Thai font on my 6600)
An alternative method to implement this will be manually drawing
your text (combile character from image font file).
I may do that some day.